1. Field of the Invention
The present invention relates to a wrench, and more particularly to, an adjustable wrench which can turn a workpiece conveniently and smoothly.
2. Description of Related Art
An adjustable wrench is used to turn a pipe member, a screw or a nut. The adjustable wrench comprises a screw member to move an adjustable jaw so that the opening between the adjustable jaw and the fixed jaw can be adjusted to clip a workpiece. In fact, it is difficult to know the size of the required opening. The screw member needs to be adjusted many times to fit on the workpiece. This is quite troublesome when in use. Besides, when the wrench is operated at an angle which is hard to turn the workpiece or there is an obstacle during the operation, the user has to adjust the wrench at a proper angel to turn the workpiece. The entire operation is complicated and the work efficiency is low.
Taiwan Patent Publication No. 136716 discloses an adjustable wrench, which uses a movable wrench to adjust the screw member and link a cylindrical rack. This wrench can turn the workpiece continuously, but it is necessary to adjust the screw member for different workpieces. It is inconvenient for use.
Taiwan Patent Publication No. 388313 discloses an adjustable wrench, which comprises a jaw body and a handle body. One end of the jaw body is pivotally connected to the handle body. The front end of the handle body is provided with a first toothed block to engage with a second toothed block at the lower edge of a movable jaw block. The handle body is swung relative to the jaw body to move the clip block, so that the opening between a first jaw of the jaw body and a second jaw of the clip block can be adjusted. Though the opening can be adjusted conveniently, there is no limit to confine the maximum and minimum opening through the swing of the handle body. It is not beneficial to adjust a desired opening with one handle. When the opening is enlarged by the angled portion of the nut, the opening cannot automatically restore to the required size for turning the workpiece. The jaw body must be applied with an external force to clip the workpiece again by the swing of the handle body. This is not beneficial to turn the workpiece continuously. When turning the workpiece, the force from the first toothed rack of the handle body to drive the clip block doesn't direct act on the track of the clip block. During slide, a part of the first toothed block compresses the second toothed block of the clip block to move. After a period of time, the slide may be jammed to influence its normal function.
Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.